Influence of Sensing Contacts on Electrochemical Impedance Spectroscopy Measurement of EV Batteries

This article deals with the influence of the design of the measuring contact of electrochemical cells on the results measured by electrochemical impedance spectroscopy (EIS). Since battery cells can reach internal series resistance values ​​in the sub milliohm range, impedance measurement becomes a problem. In general, impedance measurement in ranges smaller than 1 mΩ is problematic and makes it difficult to make contacts. Among other things, the EIS method uses injecting of excitation current. Therefore, the measuring contacts' design must have the smallest possible parasitic properties.